This application claims the priority of German Application No. 100 53 139.3 filed Oct. 26, 2000, which is incorporated herein by reference.
This invention relates to a device in a fiber processing machine, such as a carding machine or a cleaner for setting the distance between cooperating clothings, such as the clothing of the main carding cylinder of a carding machine and the clothing of a flat bar of a traveling flats assembly.
The distance between the clothing of the main carding cylinder and the clothing of a member cooperating therewith is of substantial significance as far as machine technology and fiber technology are concerned. The carding result, that is, the cleaning, nep-formation and fiber shortening is to a large measure dependent from the carding clearance, that is, the distance between the clothing of the main carding cylinder and the clothing of the traveling or stationary flat bars. The guidance of air about the main carding cylinder and the heat removal are also dependent from the distance between the clothing of the main carding cylinder and the facing clothed or even non-clothed surfaces, such as a waste separating mote knife or cover elements of the machine. The extent of the distances depend from different, partially opposed effects. The wear of cooperating clothings leads to an enlargement of the carding clearance which results in an increase of the nep number and a decrease of the fiber shortening. An increase in the carding cylinder rpm, for example to increase the cleaning effect, causes, because of centrifugal forces, an enlargement of the carding cylinder, including its clothing and thus a decrease in the carding clearance results. The carding cylinder also expands and thus the carding clearance decreases because of the temperature increase in case a large quantity of fiber is processed or particular fiber types, for example, chemical fibers are handled.
In practice, during assembly of a carding machine, first the flat bars are installed and then the distance between the clothing points of the carding cylinder clothing and the clothing points of the flat bar clothings is determined by gauges. Such a distance is measured, for example, at every other flat bar, and an average value is formed from the measured values. The flat bars of a flat bar set regularly have different heights so that the distances are accordingly different. For changing the distance between the points of the flat bar clothings and the points of the main carding cylinder clothing, that is, to set a predetermined carding clearance, the position of the flexible bend (carrying the sliding guide for the flat bars) is radially adjusted at several locations by means of set screws. Thus, by changing the position of the sliding guide, the radial position of the flat bars is altered and, as a result, the distance between the clothings of the flat bars and the main carding cylinder is set.
An adjustment of the flexible bends as outlined above is complicated, time-consuming and requires skill and experience. Further, the geometry of the flexible bend depends from the number of the circumferentially distributed set screws. It is a further drawback that the entire flexible bend cannot be adjusted in one step. It is a particular disadvantage that the differences in the height positions of the flat bars are included in the measurements. Because of these height differences and the use of a plurality of circumferentially distributed set screws, the carding clearance cannot be set in a desired manner.
In a known arrangement, as described, for example, in European Patent No. 801 158 a sensor is provided with which the working distance of the carding clothings (also termed as xe2x80x9ccarding clearancexe2x80x9d) can be measured, that is, the effective distance of the points of a clothing from a machine component facing the clothing can be determined. Such a machine component may also have a clothing but may also be, for example, a cover element provided with a guiding surface. The sensor is configured particularly for measuring the working distance between the carding cylinder and the flat bars of a traveling flats assembly. Such a working distance changes as the wear increases. By means of an optical instrument the carding clearance between the carding cylinder clothing and the flat bar clothings is to be sensed from the side of the working region. It is a disadvantage of this arrangement that the change of the carding clearance gives no indication to what extent the change is to be traced back to the different flat bars.
It is an object of the invention to provide an improved device of the above-outlined type from which the discussed disadvantages are eliminated and which, in particular, sets the carding clearance in a simple and time-saving manner.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the fiber processing machine includes a roll having a circumferential surface provided with a first clothing having clothing points; a counter member having a surface provided with a second clothing cooperating with the first clothing and having clothing points; and a device for setting a clearance between the clothing points of the first and second clothings. The device includes an arrangement for approaching the roll and the counter member to one another until the clothing points of the first and second clothings contact and for moving away the roll and the counter member from one another until the clothing points of the first and second clothings assume a desired clearance. The device further has an arrangement for emitting a signal when the clothing points of the first and second clothings contact one another.
The measures according to the invention provide for a very accurate setting of the carding clearance in a simple and time-saving manner. It is a particular advantage of the invention that the setting is carried out without changing the shape of the flexible bend and the sliding guide; as a result, the previously uniformly and precisely set flexible bend and sliding guide retain their shape. It is a further advantage that the setting of a particularly narrow carding clearance is possible. This is of significance since the smaller the carding clearance, the better the carding effect.